Assembly of the CO Dehydrogenase Bimetallic Catalytic Site

• Applicant: Professor Dr. Ortwin Meyer
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2011 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 195610414

The enzyme CO dehydrogenase from the eubacterium Oligotropha carboxidovorans accommodates in its catalytic site a metal cluster which uniquely joins the elements Mo, S and Cu in form of a [CuSMoO2] cluster. The cluster assembles posttranslationally employing apo-CO dehydrogenase as a scaffold. The primary objective of this project is to unravel the biosynthetic pathway and catalytic entities involved in cluster assembly. Employing cryoelectron microscopy, x-ray absorption spectroscopy, crystallography, electron paramagnetic resonance spectroscopy and chemical reconstruction of the active site we will examine apo- CO dehydrogenases from mutants arrested in different steps of cluster biosynthesis. Analogies of the proteins operative in cluster assembly (CoxDEF) in O. carboxidovorans with components of the bacterial Mg-chelatase complex (BchIDH) suggest that CoxDEF form an oligomeric, ring-shaped complex which partially unfolds apo-CO dehydrogenase and completes the cluster with S and Cu. CoxDEF will be expressed in E. coli and studied in vitro for structure, complex formation and exact functions. The project will significantly contribute to the general understanding of metal cluster maturation in Biology including the associated functions of AAA+ ATPase complexes.

• DFG Programme: Research Grants